Question 250605
<font face="Garamond" size="+2">


Most calculators do not have a *[tex \Large \log_4] function.  Log tables for *[tex \Large \log_4] are pretty scarce as well.  You can calculate logarithms to any base you like using Excel.  The formula is =log(number,base), where "number" is the argument of the logarithm and "base" is any base you like.


Barring that you will need to do a base conversion to find values of base 4 logs.  Note that:


*[tex \LARGE \ \ \ \ \ \ \ \ \ \ \log_b(x) = \frac{\log_c(x)}{\log_c(b)} = \frac{\ln(x)}{\ln(b)}]


Allowing you to convert from base 4 to either base 10 or base <i>e</i>] for which you have either a calculator function or a log table.


For instance:  Let's say you select -1 as one of your "greater than -3" values.  Then:


*[tex \LARGE \ \ \ \ \ \ \ \ \ \ y\ \ =\ -\log_4(x+4)\ =\ -\log_4((-1)+4)\ =\ -\log_4(3)\ =\ -\frac{ln(3)}{ln(4)}\ \approx -0.7925]


John
*[tex \LARGE e^{i\pi} + 1 = 0]
</font>